1/*
2 * ebt_log
3 *
4 * Authors:
5 * Bart De Schuymer <bdschuym@pandora.be>
6 * Harald Welte <laforge@netfilter.org>
7 *
8 * April, 2002
9 *
10 */
11#include <linux/module.h>
12#include <linux/ip.h>
13#include <linux/in.h>
14#include <linux/if_arp.h>
15#include <linux/spinlock.h>
16#include <net/netfilter/nf_log.h>
17#include <linux/ipv6.h>
18#include <net/ipv6.h>
19#include <linux/in6.h>
20#include <linux/netfilter/x_tables.h>
21#include <linux/netfilter_bridge/ebtables.h>
22#include <linux/netfilter_bridge/ebt_log.h>
23#include <linux/netfilter.h>
24
25static DEFINE_SPINLOCK(ebt_log_lock);
26
27static int ebt_log_tg_check(const struct xt_tgchk_param *par)
28{
29 struct ebt_log_info *info = par->targinfo;
30
31 if (info->bitmask & ~EBT_LOG_MASK)
32 return -EINVAL;
33 if (info->loglevel >= 8)
34 return -EINVAL;
35 info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
36 return 0;
37}
38
39struct tcpudphdr {
40 __be16 src;
41 __be16 dst;
42};
43
44struct arppayload {
45 unsigned char mac_src[ETH_ALEN];
46 unsigned char ip_src[4];
47 unsigned char mac_dst[ETH_ALEN];
48 unsigned char ip_dst[4];
49};
50
51static void
52print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
53{
54 if (protocol == IPPROTO_TCP ||
55 protocol == IPPROTO_UDP ||
56 protocol == IPPROTO_UDPLITE ||
57 protocol == IPPROTO_SCTP ||
58 protocol == IPPROTO_DCCP) {
59 const struct tcpudphdr *pptr;
60 struct tcpudphdr _ports;
61
62 pptr = skb_header_pointer(skb, offset,
63 sizeof(_ports), &_ports);
64 if (pptr == NULL) {
65 pr_cont(" INCOMPLETE TCP/UDP header");
66 return;
67 }
68 pr_cont(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
69 }
70}
71
72static void
73ebt_log_packet(struct net *net, u_int8_t pf, unsigned int hooknum,
74 const struct sk_buff *skb, const struct net_device *in,
75 const struct net_device *out, const struct nf_loginfo *loginfo,
76 const char *prefix)
77{
78 unsigned int bitmask;
79
80 /* FIXME: Disabled from containers until syslog ns is supported */
81 if (!net_eq(net, &init_net) && !sysctl_nf_log_all_netns)
82 return;
83
84 spin_lock_bh(&ebt_log_lock);
85 printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
86 '0' + loginfo->u.log.level, prefix,
87 in ? in->name : "", out ? out->name : "",
88 eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
89 ntohs(eth_hdr(skb)->h_proto));
90
91 if (loginfo->type == NF_LOG_TYPE_LOG)
92 bitmask = loginfo->u.log.logflags;
93 else
94 bitmask = NF_LOG_DEFAULT_MASK;
95
96 if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
97 htons(ETH_P_IP)) {
98 const struct iphdr *ih;
99 struct iphdr _iph;
100
101 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
102 if (ih == NULL) {
103 pr_cont(" INCOMPLETE IP header");
104 goto out;
105 }
106 pr_cont(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
107 &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
108 print_ports(skb, ih->protocol, ih->ihl*4);
109 goto out;
110 }
111
112#if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
113 if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
114 htons(ETH_P_IPV6)) {
115 const struct ipv6hdr *ih;
116 struct ipv6hdr _iph;
117 uint8_t nexthdr;
118 __be16 frag_off;
119 int offset_ph;
120
121 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
122 if (ih == NULL) {
123 pr_cont(" INCOMPLETE IPv6 header");
124 goto out;
125 }
126 pr_cont(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
127 &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
128 nexthdr = ih->nexthdr;
129 offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
130 if (offset_ph == -1)
131 goto out;
132 print_ports(skb, nexthdr, offset_ph);
133 goto out;
134 }
135#endif
136
137 if ((bitmask & EBT_LOG_ARP) &&
138 ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
139 (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
140 const struct arphdr *ah;
141 struct arphdr _arph;
142
143 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
144 if (ah == NULL) {
145 pr_cont(" INCOMPLETE ARP header");
146 goto out;
147 }
148 pr_cont(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
149 ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
150 ntohs(ah->ar_op));
151
152 /* If it's for Ethernet and the lengths are OK,
153 * then log the ARP payload
154 */
155 if (ah->ar_hrd == htons(1) &&
156 ah->ar_hln == ETH_ALEN &&
157 ah->ar_pln == sizeof(__be32)) {
158 const struct arppayload *ap;
159 struct arppayload _arpp;
160
161 ap = skb_header_pointer(skb, sizeof(_arph),
162 sizeof(_arpp), &_arpp);
163 if (ap == NULL) {
164 pr_cont(" INCOMPLETE ARP payload");
165 goto out;
166 }
167 pr_cont(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
168 ap->mac_src, ap->ip_src,
169 ap->mac_dst, ap->ip_dst);
170 }
171 }
172out:
173 pr_cont("\n");
174 spin_unlock_bh(&ebt_log_lock);
175}
176
177static unsigned int
178ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
179{
180 const struct ebt_log_info *info = par->targinfo;
181 struct nf_loginfo li;
182 struct net *net = xt_net(par);
183
184 li.type = NF_LOG_TYPE_LOG;
185 li.u.log.level = info->loglevel;
186 li.u.log.logflags = info->bitmask;
187
188 /* Remember that we have to use ebt_log_packet() not to break backward
189 * compatibility. We cannot use the default bridge packet logger via
190 * nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo
191 */
192 if (info->bitmask & EBT_LOG_NFLOG)
193 nf_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
194 xt_in(par), xt_out(par), &li, "%s",
195 info->prefix);
196 else
197 ebt_log_packet(net, NFPROTO_BRIDGE, xt_hooknum(par), skb,
198 xt_in(par), xt_out(par), &li, info->prefix);
199 return EBT_CONTINUE;
200}
201
202static struct xt_target ebt_log_tg_reg __read_mostly = {
203 .name = "log",
204 .revision = 0,
205 .family = NFPROTO_BRIDGE,
206 .target = ebt_log_tg,
207 .checkentry = ebt_log_tg_check,
208 .targetsize = sizeof(struct ebt_log_info),
209 .me = THIS_MODULE,
210};
211
212static int __init ebt_log_init(void)
213{
214 return xt_register_target(&ebt_log_tg_reg);
215}
216
217static void __exit ebt_log_fini(void)
218{
219 xt_unregister_target(&ebt_log_tg_reg);
220}
221
222module_init(ebt_log_init);
223module_exit(ebt_log_fini);
224MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
225MODULE_LICENSE("GPL");
226